Water flows into a tank through Tap M and flows out of the container through Tap N. The capacity of a tank is 54 litres. When only Tap M is turned on, the container is completely filled in 12 minutes. When only Tap N is turned on, it takes
14 hour for all the water to flow out. If both taps are turned on at the same time,
- How long does it take to fill 66% of the tank?
- How much water has flowed out through Tap N by the time the tank is 45 filled with water? Express your answer in litres.
(a)
Tap M :
12 min → 1 tank
1 min →
112 tank
14 hour =
14 x 60 = 15 min
Tap N:
15 min → 1 tank
1 min →
115 tank
Tap M and Tap N:
1 min →
112 -
115 =
560 -
460 =
160 tank
1 tank →
601 = 60 min
66% tank → 66% x 60 = 39.6 min
(b)
Time taken to fill
45 of the tank
1 tank → 60 min
45 tank → 60 x
45 = 48 min
Volume that flows out per min
=
115 tank
=
115 x 54
= 3.6 ℓ
Volume of water that flowed out through Tap N in 48 min
= 48 x 3.6
= 172.8 ℓ
Answer(s): (a) 39.6 min; (b) 172.8 ℓ